Photography – what is ISO? ISO measures the light sensitivity of the receiving element. Previously, it was film and photographic paper. Changing the ISO required removing one film and inserting another. Today, the sensitivity of the matrix is most often defined in ISO. And everything is the same, the higher the ISO value set in the camera, the less light the camera needs to get a properly exposed photo.
A bit of information about the light sensitivity of the film or matrix
ISO is not some scientifically calculated value, it is not a meter or a kilogram. ISO is the name of the standard. And in fact, many photographers dealing with photography at the end of the last century remember well the film where the sensitivity was indicated in DIN and ASA, and always provided conversion tables for these units. Today, it is quite difficult, if not impossible, to find a non-ISO standard for photosensitive elements.
In analog photography, ISO indicates the film’s sensitivity to light. It is measured in numbers (numbers on the film box – 100, 200, 400, 800, etc.). The lower the number, the lower the film speed. In digital photography, ISO measures the sensitivity of the image sensor. The same principles apply to digital ISO as to analog photography. The lower the number, the lower the camera’s sensitivity to light, and therefore the finer the grain.
Higher ISO settings are usually used when there is not enough light to achieve a faster shutter speed. For example, a photographer filming an indoor sporting event. In order to freeze motion and get a good technical shot, you will need to raise the ISO sensitivity, which unfortunately will lead to more noise in the frame. For example, a photo taken at ISO 100 has a smoother image surface than a photo taken at ISO 3200.
At ISO 100, the overall result is photos that are visually perceived as normal, resulting in excellent image clarity despite some noise/graininess.
Cameras – automatic and non-automatic photo mode
Most novice photographers or hobbyists usually prefer to shoot with digital cameras in auto mode. In this case, the camera automatically selects the appropriate ISO settings depending on the shooting conditions and tries to use the lowest possible value. Many modern models of even ordinary compact cameras are equipped with a mode in which the photographer can control the ISO.
Because this parameter is very important, and the technical quality of the photos depends on it, which always attracts attention, be it amateurs or professionals.
When beginners master non-automatic shooting modes a little, they note that when you change the ISO, the aperture value and shutter speed change. This proves that ISO directly affects aperture and shutter speed at the same time.
Even when the camera automatically selects a pair, it analyzes the values and gives those that are necessary to obtain a technically well-developed frame. For example, if your camera has ISO 100 to 400, you can take pictures with faster shutter speeds and/or use smaller apertures.
Parameter settings for shooting – the most important questions
- Light. Is the subject well lit?
- Grain. Is there a need for a grainy image surface or a clean frame without noise?
- Tripod. Is it used on set today?
- A moving object. Is the object moving or stationary?
If there is a lot of light around, the photographer wants to have the clearest frame possible, he uses a tripod to shoot a stationary subject, he can safely use the lowest possible ISO for the camera. The result is a technically well-executed frame.
What if it’s cloudy or dark outside, or you’re shooting indoors (which automatically means less light), you don’t have a tripod, and you can’t fix the camera? Also, when taking long exposure shots, you can’t avoid camera shake when shooting handheld? You need to raise the ISO sensitivity. If the subject is still in motion, then, as photographers say, the ISO will have to be raised to critical values.
This action will allow you to take a photo with a slower shutter speed, it is even quite clear and sharp, but it will add digital grain.
Situations where the photographer may need to change the camera settings to a higher sensitivity:
- Indoor sports activities. The subject is moving fast and the lighting is limited.
- concerts. Poor shooting light and not using the flash can force you to raise the ISO sensitivity to the maximum values that the camera can handle.
- Art galleries, museums, churches, etc. Existing laws prohibit flash photography. The subject should be well lit to get the right technical shot.
ISO is an important aspect in photography. Being able to manage it gives you more scope to control the actions of the camera.
A few golden rules of photography for beginners:
- It is always desirable to shoot with the lowest ISO possible
- As soon as the possibility of lowering the ISO appears – it is worth doing it
- Only increase the ISO value when necessary, such as when the shutter speed at a low ISO value is too slow for normal handheld shooting
- To use the minimum ISO value, you need to open the aperture as far as possible
- If you shoot with a flash, the ISO sensitivity should not be high.